1. Technical Field
Example embodiments relate to nonvolatile memory devices, and more particularly to a method of programming a nonvolatile memory device.
2. Description of the Related Art
In a method of programming a nonvolatile memory device, memory cells are selected according to data to be programmed. For example, in one method, a ground voltage is applied to bitlines coupled to the selected memory cells, and a power supply voltage is applied as a program inhibit voltage to bitlines coupled to non-selected memory cells. The power supply voltage is applied to a string select line, a program voltage is applied to a selected wordline coupled to the memory cells, and a pass voltage is applied to non-selected wordlines. Then channels of the non-selected memory cells are boosted to VCC−Vth (where VCC represents the power supply voltage and Vth represents a threshold voltage of a string select transistor), and string select transistors coupled to the non-selected memory cells are substantially shut off. Accordingly, Fowler-Nordheim (F-N) tunneling does not occur between a floating gate and a channel in each non-selected memory cell, and the non-selected memory cells are not programmed.
However, as integration density increases, a capacitance between channels of adjacent memory cells increases. This increased capacitance may prevent the channels of the non-selected memory cells from being sufficiently boosted. Accordingly, when a memory cell adjacent to a non-selected memory cell is programmed in the same wordline, the non-selected memory cell can be unintentionally programmed, which is referred to as “program disturb”. In particular, the program disturb is likely to occur when adjacent memory cells on both sides of the non-selected memory cells are programmed.